FIG. 1 generally illustrates a digital receiver system 1 for, as examples, radio scanner and cognitive radio applications. The digital receiver system 1 has an RF source 10, an analog front end 20, an analog-to digital converter (ADC) 30 that provides a digital input 32 to a digital front-end 100 and a channel processor/multiplexer 50 that provides an application specific output 52. The digital front-end 100 has a high resolution spectrum analyzer 110, a channel selector 120, and a channelizer 130. In radio scanner applications, the high resolution spectrum analyzer 110 provides multiple spectral bands to the channel selector 120, which identifies channels of interest for down conversion by the channel processor 50. In cognitive radio system applications, the high resolution spectrum analyzer 110 provides multiple spectral bands to the channel selector 120, which identifies channels for up conversion by the channel processor 50 for insertion into empty spectral spans.